Method of producing betaines,monomers and polymers containing betaine-type units and novel and useful copolymers thereby obtained

ABSTRACT

AN IMPROVED METHOD IS PROVIDED FOR PRODUCING POLYMERS OF ORGANIC COMPOUNDS, SUCH AS ETHYLENICALLY UNSATURATED MONOMERS, CONTAINING A BETAINE-TYPE GROUP OF THE FORMULA:   -N(+)(-R)2-R-COO(-)   THE METHOD INVOLVES THE REACTION OF ACRYLIC ACID OR AQUEOUS METHYL ACRYLATE AND AN AMINOALKYL (METH) ACRYLATE OR AN N-AMINOALKYL (METH) ACRYLAMICE HAVING A BASIC TERTIARY NITROGEN ATOM IN THE PRESENCE OF A FREE RADICAL INITIATOR. THE MONOMERS UNDERGO VINYL ADDITION POLYMERIZATION TO FORM VALUABLE POLYMERS HAVING A WIDE VARIETY OF USES, SUCH AS FLOCCULANTS, RETENTION AIDS IN THE DEPOSITION OF POLYMERS, PIGMENTS, ETC. ON THE FIBERS IN A PAPER PULP, E.G., IN THE FORMATION OF MINERAL-FILLED PAPERS.

United States Patent METHOD OF PRODUCING BETAINES, MON OMERS AND POLYMERS CONTAINING BETAINE-TYPE UNITS AND NOVEL AND USEFUL COPOLYMERS THEREBY OBTAINED Norman Shachat, Levittown, Richard A. Haggard, Fort Washington, and Sheldon N. Lewis, Willow Grove, Pa., assignors to Rohm and Haas Company, Philadelphia, Pa. No Drawing. Filed Sept. 10, 1969, Ser. No. 856,822

Int. Cl. C08f 15/14, 15/16, 3/90 US. Cl. Mil-86.1 N 3 Claims ABSTRACT OF THE DISCLOSURE An improved method is provided for producing polymers of organic compounds, such as ethylenically unsaturated monomers, containing a betaine-type group of the formula:

The method involves the reaction of acrylic acid or aqueous methyl acrylate and an aminoalkyl (meth)acrylate or an N-aminoalkyl (meth) acrylamide having a basic tertiary nitrogen atom in the presence of a free radical initiator. The monomers undergo vinyl addition polymerization to form valuable polymers having a wide variety of uses, such as flocculants, retention aids in the deposition of polymers, pigments, etc. on the fibers in a paper pulp, e.g., in the formation of mineral-filled papers.

PRIOR ART Classical methods for producing betaine-type compounds are by reaction of a tertiary amine with betapropiolactone (see, for example, Fiedorek, US. 2,548,- 428) and by reaction of a tertiary amine with an whalo acid salt (see, for example, Schuller et al., US. 2,958,- 682). Toxicity and reagent expense are economically unfavorable in the former and the thermal and pH reaction conditions required for the second method are serious deficiencies for labile reagents.

DESCRIPTION OF THE INVENTION It is an object of the present invention to provide new rnethods for producing betaine-type compounds generally, including polymerizable unsaturated types thereof and polymers of the latter. It is an object to provide such a method that utilizes commonly available, relatively nontoxic, and inexpensive starting materials. Another object is to provide a method of this type which does not require high temperatures to attain good yields. Other objects and advantages will be apparent from the description of the invention hereinafter.

While the compounds obtained by the process of the present invention do not all fall within the strict definition of betaines, they can be referred to as of betaine-type by virtue of the quaternary ammonium nitrogen atom which is substituted by a carboxyl-containing radical and the fact that they form an inner salt as is indicated in the formula hereinafter given in Equation A. For convenience, the compounds obtained by the process of the invention may sometimes herein be referred to as a betaine, a betainetype compound or as an inner salt of the N-(Z-carboxyethyl) quaternary of the tertiary amine from which the 3,689,470 Patented Sept. 5 1972 compound is derived; for example, the expression N-(Z- carboxyethyl) inner salt of dimethylaminoethyl acrylate (DMAEA) may be applied to the product obtained by reaction of acrylic acid with 'D-MAEA.

One method of the present invention involves the reaction of a tertiary amine with acrylic acid according to the following equation:

The reaction, insofar as the amine is concerned, is applicable generally to aliphatic and substituted aliphatic amines. The 'R, R, and R substituents may be of any aliphatic composition provided they are not reactive otherwise toward the acrylic acid under the conditions prevailing during the betaine-producing reaction. Thus, these substituents may be any alkyl group, cycloalkyl, such as cyclohexyl, aralkyl, such as benzyl, vinylbenzyl (0, m, or p), alkenyl, such as allyl, hydroxyalkyl, alkoxyalkyl, polyalkoxyalkyl, acryloxyalkyl, acryloxyalkoxyalkyl, acryloxypolyalkoxyal-kyl, the corresponding methacryloxy-substituted alkyl and alkoxyalkyl groups and the corresponding acrylamidoor methacrylamido-substituted alkyl and alkoxyalkyl groups. Any two of these three substituents may be joined together to form with the N atom a cyclic group having 5 to 6 atoms (of C, O, S, or N) in the ring, such as morpholino, thiomorpholino, N-alkylpiperazino and piperidino groups. The size of the various substituents on the -N atom of the tertiary amine is limited only by the manifestation of steric hindrance. However, when all three of R, R and R are alkyl or aralkyl groups, they may have 1 to 8 carbon atoms, or one of the three may have as many as 24 carbon atoms, provided the other two have not over 8 carbons each and preferably from 1 to 4 carbons in each. One of the three substituents may be a hydroxyalkyl group of 2 to 24 carbon atoms, an alkoxyalkyl group of 3 to 24 carbon atoms, or a poly(alkyloxy) alkyl group having 2 to 6 oxygen atoms and 2 to 3 carbon atoms in all of the alkyl groups except one of the terminal alkyl groups which may have 1 to 8 carbon atoms, preferably 2 to 4. The other two substituents are then preferably alkyl having 1 to 4 carbon atoms. One of the substituents may be one of the groups named above containing an acryloxy, methacryloxy, acrylamido or methacrylamido radical. Such named group may have an alkyl component of 1 to 10 carbon atoms, an alkoxyalkyl component of 3 to 24 carbon atoms, or a poly(alkoxy)alkyl component of the same composition as that designated above for such a group unsubstituted by an acryloxy, methacryloxy, acrylamido, or methacrylarnido group. In these cases, also,

the other two substituents are preferably (C -Cgalkyl groups.

In summary, in one preferred group of tertiary amines,

In another preferred group of tertiary amines that are adapted to produce polymerizable monomers:

R is a group selected from (C -C )alkyl which is substituted by an acryloxy, methacryloxy, acrylamido or methacrylamido group,

R is (CC -C )alkyl, and R is (C -C )al-kyl.

The reaction of a tertiary amine and acrylic acid may be carried out without a solvent or in an aqueous or nonaqueous medium. In an aqueous medium, the reaction may be carried out between and about 100 C. at atmospheric pressure. At a given concentration of reactants (tertiary amine and acrylic acid), the equilibrium concentration of betaine increases as the temperature is decreased. However, the rate at which equilibrium is achieved increases with increasing temperature. A preferred temperature range is 10 to 40 C.

The total concentration of acrylic acid and amine in the solvent medium may be anywhere from to 99% by weight and is preferably about to 50% by weight. Generally, a relatively large ratio of acid to amine is preferred in order to favor the shift of the equilibrium toward the formation of the betaine. For practical purposes the ratio of acid to amine is from 0.121 to 10:1 and preferably 1:1 to 5:1.

For example, 2.5:1 to 3.5 :1 mole ratios can provide equilibrium conversions of amine to betaine as high as 90-95%. In certain cases, the betaine reversal to reactants in Equation A is slow enough to permit isolation of the betaine. An appropriate choice of solvent may be used to cause precipitation of the betaine product, further shifting Equation A to the right. For most purposes, betaine isolation is unnecessary preparatory to use, the reaction mixture being suitable for direct use, as by polymerization.

As stated above, the range of temperature at which the reaction can be effected is quite wide. Broadly stated, it can be at any temperature above the freezing point of the reaction mixture and below the boiling point of the reaction mixture With a further qualification that when a hydrolyza-ble amine, i.e., an amine containing a hydrolyzable substituent, such as dimethyl(acetoxyethyl)amine, is used, that the temperature during the reaction is not so high as to hydrolyze the amine extensively. If the medium is basic, hydrolysis of acyloxyalkyl amines is favored. This can be reduced by including sufficient acid to render the medium at least neutral and preferably acid, e.g., a pH of 3-4.5. To limit hydrolysis under these conditions, it is preferred that the ratio of acid to amine be in excess of 1:1.

In the case of the production of polymerizable monomeric betaines, the use of two moles of acrylic acid for each mole of the tertiary amine such as dimethylaminoethyl methacrylate often produces what appears to be a complex of one mole of the betaine with one mole of the acid which often precipitates when the reaction is carried out under anhydrous or essentially anhydrous conditions.

The betaine product may be recovered by any methods well known to workers of average skill in the art.

Another improved method of the present invention is the reaction of the tertiary amine with an acrylic acid ester. Equation B represents this reaction:

This reaction requires water. The betaine product is not in equilibrium with the starting alkyl acrylate but is subject to reversal to acrylic acid as in Equation A. The reaction occurs at room temperature although the range of temperature may be from as low as 0 C. up to about '4 100 C. and preferably in the range of 10-40" C. The same amines as those mentioned in connection with the method using acrylic acid, which are free of functional groups susceptible to hydrolysis under basic conditions, can be used in this method.

When the two methods are carried out with a polymerizable tertiary amine in which R is a group selected from (C C )alkyl which is substituted by an acryloxy, methacryloxy, acrylamido or methacrylamido group, a free radical initiator may be included in the reaction system to effect polymerization simultaneously with the production of the betaine.

The method using acrylic acid has specific advantages when it is desired to produce monomeric betaines from hydrolyzable tertiary amines which are adapted to produce polymerizable betaine-type monomers, such as those tertiary amines in which one of the R groups is an acryloxyor methacryloxy-substituted alkyl group or the like.

The two methods mentioned hereinabove are applicable as well to the treatment of polymers containing tertiary amine groups, such as polymers of the N-dialkylaminoalkylamides of acrylic acid or methacrylic acid, especially those in which the alkyl groups contain up to 4 carbon atoms. The methods are applicable also to the analogous polymers containing units formed from dialkylarninoalkyl esters of acrylic acid or methacrylic acid which, as polymeric units, are much less subject to alkaline hydrolysis than the respective monomer. The reaction temperature may be about 0 C. to 100 C., elevated temperatures being preferred. Basic conditions may prevail, when an ester is used. With acrylic acid, neutral to acid pH is used. The polymer reactants contain 1% to 100% of t-amine containing units. The polymers may be prepared in any way, such as by solution, emulsion, bulk, or suspension polymerization techniques.

The betaines produced are known products useful for various purposes in industry and commerce. Especially advantageous products are those containing a polymerizable group such as a vinyl, allyl, acryloxy, methacryloxy, acrylamido, or methacrylamido group therein. Polymers of such products find use as flocculants, pigment retention aids in the mineral filling of paper and soil release treatments for textiles as described in a copending application having a common assignee Serial No. 7,268, filed January 30, 1970.

While excess acrylic acid or methyl acrylate in the products obtained may be removed, nevertheless, for many purposes there is no necessity to remove the excess acid or acrylate ester from the polymerizable monomeric betaine since the acrylic acid or ester copolymerizes with the betaine to produce desirable products of polymeric character useful for similar purposes such as for flocculation, anchoring of polymers to the fibers of paper pulp, pigment retention aids in the formation of mineral filled papers and the like.

To assist those skilled in the art to practice the present invention, the following modes of operation are suggested by Way of illustration, parts and percentages being by weight and the temperature in C. unless otherwise specifically noted.

(1) Reaction of acrylic acid (AA) and ,B-N,N-dimethyl aminoethyl methacrylate (DMAEMA) (A) In aqueous solution.-A solution of 72 parts DMAEMA, 33 parts AA (1:1 molar ratio DMAEMA: AA) and 0.5 part p-methoxyphenol (MEHQ) in 245 parts H O is stirred at 25 C. Periodically, samples are removed and analyzed by titration for betaine formation. Betaine is determined by the decrease in amine titer. The equilibrium mixture containing about 11 parts DMAEMA, about 5 parts AA and about 86 parts of the N-(Z-carboxyethyl) inner salt of DMAEMA is achieved in about 25 days. The pH of the product mixture is 5.1. Thus, the conversion of amine to betaine at equilibrium under the above conditions is about Other experiments carried.

out in similar fashion are summarized in the following The results show that about 83% of the amine is contable: verted to betaine and that most of the remaining methyl acrylate is hydrolyzed to methanol and AA.

TABLE I Conversion of amine Molar Product composition (parts) Appro betaine Starting materials (parts) ratio, at eq. time to at eq.

AA: T. achieve (per- DMAEMA A Water MEHQ DMAEMA C.) DMAEMA AA Betaine eq. (h1'.) cent) pH at eq 72.0 16.5 245 0. 5 0.5 so 1 41. s) 1.7 45.0 7 42 1 (4.8) 72.0 33. 245 0. 1. 0 27. 12. 6 65. 0 2 62 5. 2 72. 0 99. 0 245 0. 5 3. 0 s0 14. 7 72. 7 s3. 6 3 79. 5 a. 4 72. 0 33. 0 245 0. 5 1. 0 60 19. 2 a. s 77. 0 7-24 73. 3 5. 0 412 138 400 1. 0 25 55. 2 24. 5 520. 3 600 86. 6 6.3 144 132 490 2. 0 25 6. 5 69. 0 200. 5 120 95. s 4. 0 72.0 99. 0 245 0. 5 3. 0 25 1. 7 66. s 102. 5 70 97. 6 a. 6 72. 0 99. 0 245 0. 5 3. 0 60 s. 2 69. s 93. 0 4 88. 6 3. 6 72. 0 99. 0 245 0. 5 5. 0 40 4. 1 67. s 99. 1 24 94. a 3. 6 144 198 490 a. 0 25 0. 0 132 210 120 100 5. 5 157 258 555 4. 25 0.0 216 229 120 100 4. 0

'.I.itration shows that a portion of the DMAEMA is hydrolyzed to methacrylic acid and B-N,N-dimethylaminoethanol.

(B) In nonaqueous solution.-A mixture of 36 parts DMAEMA and 33 parts AA (1:2 mol ratio) is prepared (3) Reaction of poly (DMAEMA) and (MA) at 0 and stirred at 25. Periodically, samples are removed Solution consisting of 150 parts DMAEMA (1 molej 30 and analyzed by titration for betaine formatlon. At the Parts Triton X 405 (t octylphenoxypoly(39)ethxsh end of 2.5 hours, the mixture contains 26 parts of the N- 5 ethanol), 0005 part FeSO4 7H2O and 6493 Parts water y y F Salt of (greater than is cooled to C. and a solution of 0.6 part ammonium 510% amlne conYerslon- The equlhbmim mlxtilre after persulfate in 10 parts water is added. The heat of polymh s contains about 39 Parts betame (the Inert erization carries the temperature to about C. within referre Parts DMAEMA and 21 F Wlth minutes. Polymerization is completed by addition of seeding the mixture could be induced to precipitate greater 30 0.1 part ammonium persulfate in 5 parts Water three than 75% y of a 1:1 11101 ratlq 'j P times at l-hour intervals. The polymer solution e xhibits Oth r exp are earned out sumlar fashlon with the following properties Percent Total Solids (T S larger DMAEMA ratios and all reach equilibrium within 172; Titer, L13 meqjg' 6 solution (pKa=71) 20-2 To the polymer solution there is added 150 parts (ap- (2) Reaction of (AA) or methyl acrylate (MA) and proximately 2 moles) methyl acrylate. The properties of N-dimethylaminoethanol (DMAE) the solution are followed on storage at room temperature (A) Anhydrous with AA.A solution of 35.6 parts as DMAE and 28.8 parts AA in 200 parts 1,2-dimethoxy- TABLE III Amine titer Brookfield Percent amine Percent viscosity 60 Meq./g. of converted to Time (days) T.S. pH r.p.m. (cps) soln. pKa betaine ethane is prepared at 25, and warmed to 70. Within (4) Reaction of Poly(DMAEMA) and (EA).Pro-

15 minutes, crystals of product form; the mixture is set cedure (3) above involved a ratio of MA to DMAEMA aside for 3 days at 25 and filtered, washed with 10 C. of about 2. This procedure is repeated changing the ratio dimethoxyethane and the filter cake dried to yield 40-42 to 1.0. After 3 days 63.3% of the amine in the polymer parts of betaine (the N-(Z-carboxyethyl) innert salt of 1s converted to betaine. After 11 days 76.4% is so con- DMAE), an hygroscopic white solid of M.P. 120-122". verted, and after 65 days 81.2% is so converted. When Further standing of the mother liquor for several days the same procedure is carried out but with the ratio lowyielded another 6-8 parts of the betaine, raising the total ered to 0.5, 37.5% of the amine is converted to betaine isolated yield to 71-75% of betaine. after 3 days, and 43.7% is converted after 11 days.

(B) In aqueous solution with MA.--17.8 parts ,8-N,N- When the same procedure is carried out except that dimethylaminoethanol (DMAE) and 17.2 parts methyl ethyl acrylate (EA) is used with a mole ratio of EA acrylate are diluted to a total of 500 parts with water. The to DMAEMA in the polymer of 1.0, 52.2% of the amine mixture is kept at room temperature (-25 C.). Aliquots is converted to betaine after 7 days, 64.5% is converted are periodically removed and titrated to determine the after 13 days, and 82.8% is converted after 97 days. amount of betaine formed. The results are as follows: When this procedure is repeated but using a lower ratio TABLE II of 0.5, 38.7% of the amine is converted to betaine after 7 days, 44.2% is converted after 13 days, and 45.7% is Titer converted after 97 days.

carbmylic acid Amine g g fi When procedure (3) is repeated but replacing the Meq./g. MeqJg. oiamine methyl acrylate with butyl acrylate (BA) at a mole ratio 501m to betaine of 1.0 instead of about 2, 1 8.4% of the amine is con- (8-98; verted to betaine after 7 days, 20.2% is converted after 0.336 315 0. 123 913 69:2 13 days, and 49.9% is converted after 97 days. At a lower 8' 882g 8'; 53:3 mole ratio of 0.5, somewhat lower conversions are ob- 01358 3. 5 0:07 9: 0 tained in corresponding times. For example, 44.3% of the amine is converted to betaine after 97 days.

7 (5) Poly(DMAEMA) solutions prepared as in (3) above are separately mixed with AA in the ratios given in Table IV which in the second column gives the pH (c) In similar fashion (to part b) the following copolymers are prepared:

TABLE VI values of the resulting mixtures at 25 C. The reactions Convey are carried out at the temperatures indicated in the 5 Percent $1011 to Viscosit table and the proportion of DMAEMA units converted to 00111905100 Percent) PH tain u its at C r times are noted- 20lVIA/49.1betaine/30.9AA 21.4 95.0 45 17,600 TABLE Iv A %I e EaPe/nfiiZi 20.7 95.0 6.0 3,600

l B81118 Wt. ratio Solution Reaction Percent conversion mgxgg igfigfi filffixxif 21-5 96.9 12-0 670 AA/polyDMAEMA n 25 temperature in (time 1 DMAEMA 21.0 93.4 i 1.8 840 4.7 W 53% (2O hm). 61.4 betaine/38.6 AA 9 34,000

g; 222 1 pH is not post-adjnstedwith 25% NaOH. I 5. 3 5 y (8) An emulsion is prepared from the following mgredients: 488 parts betaine/AA solution prepared in A mixture of 100 part DMAEMA, 100 Parts 7(a) above, 12 parts sodium isodecylphenoxypoyl(40) 0655) MA Parts Trltofl X405, -Q P '4' 2 ethoxy sulfate, 24 parts concentrated H 50 190 parts and 759.3 parts water is treated with a solution of 0.6 H 0, 200 parts th l cr l t and 0.8 part ammonium part ammonium persulfate in 1 p rts W r t 25 persulfate. A solution of 0.02 part FeSO -7H O in. 973.6. Polymerization occurs slowly as 1ndicated by a rise in 20 parts H 0 i h t d t 62, C, with stirring, the above temperature and an increase in viscosity. After about an emulsion is added gradually 15 parts per minute) 9 Catalyst Charges, each conslstmg 0f P ing a period of about 1 hour while the temperatureis ammonium} persulfate in 5 Parts water, are added at about maintained at 62 0. by the heat of polymerization. As a al hour lntervals- O11 at room temperature, t separate feed, a solution of 0.8 part sodium metabisulfite P 9 undergoe? the followlng Changes lnlpfopeftles 25 in parts water is added simultaneously 0.5 part per indicative of reaction of poly (DMAEl\ /IA) w1th MA [0 minute). About 25 minutes after the addition, a solution give polymer-contaming betaine functionality. of 0.2 part APS in 20 parts H 0 and a solution of 0.2 g.

TABLE v Brookf eld Amine titer Percent Time Percent r ii ii i Me l i (days) Appearance T.S pH (cps) of it 1 pK. l l l isle 0 Opaque 14.6 8.7 1,380 0.491 7.3 22 1 Hazy 0. 357 7. 3 43. 3 5 Clear 6,730 0.197 7.5 68.8 s --do 0.167 7. 7 73.5 22 do 7, 750 0. 142 7. 7 77. 5

In similar ei periments with ethyl acrylate, about 30% sodium hydrosulfite in 20 parts H 0 are added separately. betaine formation occurs in thirteen days. About 15 minutes later the preceding step is repeated. (7) (a) A mixtur f 475 parts acrylic id, 345 parts The batch is cooled to 25 C., filtered through cheesecloth DMAEMA and 1180 parts H O is allowed to react at g p gg f g g g g 3 ii i g 3 room temperature. Within 96 hours all of the amine is a on a I 0 4 an 0 etame converted to betaine, giving an aqueous solution containcarboePhoxwmnef Salt of DMAEMA) and displays the ing 61.4% betaine and 38.6% acrylic acid. This solution followmg propertles: is used to prepare a polymer as follows: Percent (b) 293 parts of the betaine/AA solution obtained in 5 Percent Converslon to Polymer (a) above, 544.8 parts H 0, 15 parts concentrated H 80 H 80 parts MA, 6 parts sodium isodecylphenoxypoly(40) Vlscoslty 550 ethoXy sulfate and 0.01 part F SO -7H O are mixed at (9) 7 Parts (MEHQ iPhibied) and 135 Parts room temperature (Co. 23 C.). The temperature of the benzyidlmethylamme (mole h of AAA amine) mixture is adjusted by heating to about 30 C. Polymeria med at 0 P 6 g g i g and i Zation is omogeneous mixture is roug tto 1- Wit nsevera Sulfate z g g zg igg fi g part amnflomum hours a viscous precipitate of betaine(N- (Z-carboxyethyl) 0 4 art d h 111 P 5 Water Qllowed y inner salt of benzyldimethylamine), complexed with p so ium ydrosulfite (SI-TS) dissolved in 10 parts excess AA, precipitates from the mixture. The small water. The; heat of polymerization carries the temperaamount of acid-depleted, mobile Supernatant liquid after ture to 61 C. in about 1 hour, Ab 20 minutes ft hours is essentially pure benzyldimethylamine. Aliquots the peak temperature i reached, 0 part APS in 10 Parts of the reaction mixture are removed periodically, treated water and part SHS in 10 Parts Water are added Se with a known amount of excess aqueous HCl and potenamtely About 15 minutes later 01 Part APS in 10 P :2 tiometrically titrated. Table VII summarizes the titration water and 0.1 part SHS in 10 parts water are added sep- 65 dataarately again. The dispersion is cooled to 25 C. and the TABLE VII pH is adjusted from 2.1 to 5.8 with 136 parts of 25% Meq-amme 1aqueous sodium hydroxide. The hazy viscous Product con- 7 efl Apgglxehgfig ains a copolymer of about 40% MA, 23.2% acrylic acid, Aliq t 9 at Q% g *gfiggggg and 36.8% of N-(2-carboxymethyl)inner salt of No 1 h f e us 0 25 3 50(s3) 1 2 DMAEMA and exhibits the following properties: g 31 gg g 1 m g- O. 5 I6 S n T.S .--20.8 (conversion to polymer about 94%), vis- No. 4, crude r eiiiitate 65 311(1160.-- cos1ty-11,400 cps. 6. ca. 0.1

No. 5, decantate .I 65 and 160..-

(10) The same parts by weight as in .(9) above are mixed in 500 parts ice water and the resutling clear solution divided into two portions, one maintained at 60:3" and the second at 251-2". Homogeneous aliquots are removed periodically and titrated as described above. Table VIII summarizes the titration data. Equilibrium is established in about 5 hours at 60 (60% conversoin) and about 12-15 days at 25 (80% conversion).

TABLE VIII Mcq. amine In situ Reaction found (per conversion time, hrs. cent of startto bctaine Aliquot, 3.60 g. (T.,l C.) ing amine) (Percent) I 4.5(60) plus 16(25") TABLE IX Meq. amine Reaction (percent of time, startin Aliquot, 0.90 g. hrs. (25) amine No. 1, homogeneous 0. 25 4. 7(94) No. 2, stirred slurry 18 ca. 3 (ea. 60) No. paste 3. 0(60) No 4, semi-solid-. 160 1. 7(34) No. 5, recrystallized betaine (160) 0 (12) The same parts by weight of acid and amine as in procedure (11) are mixed in 500 parts ice water and the resulting clear solution divided into two portions, one maintained at 60:3" and the second at 25:2. Homogeneous aliquots are removed periodically and titrated (Table X). Equilibrium is established in -6 hours at 60 (about 50% conversion) and about 12-15 days at 25 ,(about 70% amine conversion).

TABLE X Approximate meq. amine In situ found (perconversion Reaction time cent of startto betaine Aliquot, 3.40 g. hrs. ('l., 0.) ing amine) (percent) 1 4.5030") plus l6(25).

(13) 150 parts of AA (inhibited by MEHQ) is mixed with 50 parts of N-diethylaminoethyl)-acrylamide and the mixture is heated to 90 C. and maintained at that temperature for 25 hours, producing the corresponding betaine type compound, namely, the N-(Z-carboxyethyl) inner salt of N-(diethylaminoethyl)acrylamide.

(14) 75 parts of inhibited AA is mixed with 60 parts of allyldibutylamine and the mixture is heated to 45 C. and maintained at that temperature for 45 hours, with the production of the N-(2-carboxyethyl)inner salt of allyldibutylamine.

(15) 65 parts of inhibited AA is mixed with di(methoxyethy1)vinyl amine and allowed to react at 30 C. for

10 96 hours, thereby producing the N-(2-carboxyethyl)inner salt of di(methoxyethyl)vinyl amine.

' (16) 150 parts of inhibited AA is mixed with 60 parts of N-dibutylaminopropyl-methacrylamide. The mixture is heated to 50 C. and maintained at that temperature for 30 hours, thereby producing the N-(2-carboxyethyl)inner salt of N-dibutylaminopropyl-methacrylamide.

(17) The N-(2-carboxyethyl)inner salt of diethanolmethylamine is obtained by heating a mixture of 70 parts of inhibited AA and 65 parts of diethanolmethylamine at 35 for 72 hours.

(18) The N-(Z-carboxyethyDinner salt of cyclohexyldimethylamine is produced by heating a mixture of 70 parts of inhibited AA and 65 parts of cyclohexyldimethylamine at 40 for 60 hours.

(19) The N-(2-carboxyethyl)inner salt of hydroxyethoxyethyldiethylamine is produced by heating a mixture of 70 parts of inhibited AA and 65 parts of hydroxyethoxyethyldiethylamine at 40 for 60 hours.

(20) parts of inhibited AA is mixed with parts of poly(20)ethoxyethyldipropylamine. The mixture is heated to 65 and maintained at that temperature for 24 hours with the production of the N-(2-carboxyethyl)inner salt of poly(20)ethoxyethyldipropylamine.

(21) The N-(2-carboxyethyl)inner salt of dimethylaminoethoxyethyl methacrylate is obtained by heating a mixture of parts of inhibited AA and parts of dimethylaminoethoxyethyl methacrylate at room temperature for 5 days.

(22) 75 parts of inhibited AA is mixed with 85 parts of morpholinoethyl methacrylate and the mixture is heated to 45 C. and maintained at that temperature for 45 hours, with the production of the N-(2-carboxyethyl)inner salt of morpholionoethyl methacrylate of the formula 00011201120 63 omom H2C=C(CH3)COOCH2CHN /O c zCHz (23) 75 parts of inhibited AA is mixed with 85 parts of piperidinoethyl methacrylate and the mixture is heated to 45 C. and maintained at that temperature for 45 hours, with the production of the N-(Z-carboxyethyDinner salt of piperidinoethyl methacrylate of the formula 00011201120 onion,

mo=owm oooomomn CH2 omen,

We claim:

1. A method of producing a polymer containing betainetype groups comprising subjecting a mixture of (a) a dialkylaminoalkyl acrylate or methacrylate or an N-dialkylamino-alkylacrylamide or -methacrylamide of the formula wherein R is a (C -C )a1kyl group substituted by an acryloxy, methacryloxy, acrylamido or methacrylamido group,

R' is (C C )alkyl, and IR iS (C -C )alkyl,

and (b) acrylic acid in a medium containing a free radical initiator to polymerization conditions at a temperature from about 0 C. to about 100 C., the total concentraton of (a) and (b) being from 5 to 99% by weight in the reaction medium, and the molar ratio of (b) to (a) being from 0.1 :1 to 10:1, thereby producing a polymer containing dialkylaminoalkyl acrylate or methacrylate or N-dialkylaminoalkyl-acrylamide or -methacrylamide units in which the basic nitrogen atom is quaternized by a group of the formula CH CH COO.

1 1 2. A method of producing a polymer containing betainetype groups comprising subjecting a mixture of (a) a dialkylaminoalkyl acrylate or methacrylate of the formula wherein R is a (C -C )alkyl group substituted by an acryloxy or methacryloxy group,

R is (C -C alkyl, and R is (C C )alkyl,

and (b) acrylic acid in a medium containing a free radical initiator to polymerization conditions at a temperature from about 0 C. to about 100 C., the total concentraton of (a) and (b) being from 5 to 99% by weight in the reaction medium, and the molar ratio of (b) to (a) being from 0.1:1 to 10: 1, thereby producing a polymer containing dialkylaminoalkyl acrylate or methacrylate units in which the basic nitrogen atom is quaternized by a group of the formula CH CH COO-.

References Cited UNITED STATES PATENTS 2,976,263 3/1961 Anaheim et a1. 260-803 N 2,980,657 4/1961 Melamed 26080.3 N 3,032,538 5/ 1962 Spaulding et a1. 260-803 N 2,777,872 1/1957 Shacklett 260-803 N 3,014,896 12/1961 Colwell et a1. 260-803 N 3,321,451 5/1967 Gander 26086.1 N

HARRY WONG, 111., Primary Examiner US. Cl. X.R.

UNITED STATES PATENT OFFICE (IERTIFICATE OF CRRECTEON Patent No. 7 3 Dated September 9 1972 Inventor(s)NOII118.I1 Shachat, Richard A. Haggard and Sheldon N. Lewis It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Col. r, line +5, change the period to a comma and insert --now U. S. Patent 3,671,305, granted June 20, 1972.

Table I, in the second from last column, change the third item namely 3 to 2 Claim 3 line 3 after "polymer" insert -is produced-.

Signed and sealed this 6th day of March 1973.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents FORM PO'WSO USCOMM-DC 60376-P69 U.$. GOVERNMENT PRINTING OFFICE; 9H9 0-356-3 4 

